Core drilling apparatus



Nov. 28; 1950 F. C. STURGES ETAL CORE DRILLING APPARATUS Filed Oct. 17, 1949 INVENTOR FRANK. C. STURGES RUSSELL B. STROPE ATTORNEY Patented Nov. 28, 1950 CORE DRILLING APPARATUS Frank C. Sturges, Pittsburgh, and Russell B.

Strope, Rennerdale, Pa., assignors to Pennsylvania Drilling Company, Pittsburgh, Pa., a corporation of Pennsylvania Application October 17, 1949, Serial No. 121,664

Claims. (01. 255-72) This invention relates to core drilling apparatus and more particularly, it is concerned with structures combining a shot core drill with a core puller in a single unit together with novel arrangement for operating both the core drill and the core puller from a single drill rod.

The shot core drill is the standard piece of boring apparatus employed in the rock-drilling field for boring large diameter holes. The most common form of the shot core drill is the drillrod type in which the bit is rotated by a hollow rod driven by gearing located on the surface. When the bit has penetrated to a depth equal to its height, the core must be removed from the drilling before further work can continue. Small cores up to about 20 inches in diameter are released by introducing small pieces of gravel into the wash water flowing to the rotating bit. The gravel becomes wedged between the bit and the core, breaking off the latter and holding it securely enough so that it can be raised to the surface with the bit.

In recent years, the scope of usage of the shot core drill has been expanded. Thus, this type of apparatus is now being employed in the drilling of mine shafts, ventilating shafts for mines, escape shafts, and the like. This raises the size of the cores to 36 inches in diameter or larger and the cores of this size must be removed by a different method from that employed with the smaller types of cores. Practice in the past has made use of two separate pieces of apparatus in this type of operation. First, the core is drilled with the standard type of shot core bit and after a core of sufiicient depth has been out, the drill barrel is lifted out of the hole by means of the hoist on the surface. After excess water is withdrawn by a baler or pump, the core is either broken off at its base by a man lowered into the shaft, by driving wedges along one side or by explosion of a small charge of dynamite after which the core is lifted out by means of a cable fastened to the top. A second method of removing the core makes use of a core puller which is generally cylindrical in size and which slips over the core. The core puller is provided with wedges or other gripping means which grasp the core and can be used to break it off and lift it to the surface.

A principal object of this invention is the provision of new core drilling devices which elimi- A nate the necessity of employing separate core drills and core pullers. Further objects include, 1) the provision of shot core drills provided with a built-in core lifting device;

(2) the provision of a new method for drilling large-size cores and removing the cores from the drilling without requiring the insertion of separate core pulling apparatus or mechanism into the hole subsequent to withdrawal of the core drill;

(3) the provision of new mechanisms which make it possible to operate both a core drill an a core puller from a single drill rod.

' Still further objects and the entire scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

These objects are accomplished according to the present invention by the provision of a shot core drill having a core puller of the contractible, slotted type disposed coaxially within the barrel and means which causes the drill to operate freely of the core pulling section when the drill rod is rotated in one direction and actuates the core puller for gripping of the drilled core upon rotation of the drill rod in the opposite direc tion.

The new procedures and structures of this invention will become more apparent from the detailed description given hereinafter, with reference to the accompanying drawings, in which:

Figure 1 is a vertical cross section of the preferred form of the new drilling devices of this invention, showing the apparatus in position for drilling;

Figure 2 is a sectional side view of the apparatus shown in Figure 1, showing the relationship of parts of the device when it is in position to remove the core.

Referring in detail to the drawings, the core of the shoe back to the barrel. The shoe Ill also tened to-the barrel 4 by means of rivets 2|].

The head plate :2 of the barrel l is divided into two sections consisting of a circular plate 22 fastened, such as by Welding, to the barrel and a key plate 2 2-, fastened by bolts 26 to the plate 22. Fastened to the key plate 2:3 is an inside threaded tubular member 28.

An outside threaded tubular member 30 is threaded through the member 28 and connects with the core puller 5 through the support member 32 which is fastened to the upper end of the puller 5. The tubular member 35 is .free to rotate relative to the puller 5 by being connected to the member 32 through the bearingst i and :35 which are pressed upon either side of the member '32 by means of the nut 38 on the lower end 46 of the member 3%. Nut 38 is held in position upon the tubular section 30 by means of the pin 42.

A key plate 4 5 is fastened upon thetubular member as above the bearing as and below the head plate l2. Keys is are carried by the plate 14 which work in cooperation with the keys 48 carriedby the plate 24, as will be explained more fully below.

'The core puller 5 has slots 51} in the lower end thereof and wedge dogs 52 which form contractible en aging members for breaking and lift- .ing of 'a drilled core. There is also providedon the inside of the puller {5 a shot dispersing cone 5:3 held in position below the end M! of the'memher so uponbolts 56.

Y 'Adescription of'the apparatus is completed by reference to drill rod Ed having flanged end which is bolted to the flanged end 62 of the member 39 by bolts 64.

The operation of the device'is as follows: The drill rod 53 is rotated in one direction until movement of the threaded section fall within the member :28 causes the core puller '5 to be lifted relative to the barrel 4 and keys engage keys 6'8. As long as rotation in this direction of the drill rod se is continued, the core puller 5 will remain in the drawn-up position, as shown in Figure 1. With the apparatus so arranged, the device is lowered into the hole and drilling commenceddn normal fashion by'rotation of the drill through the'irod whilewater and shot are supplied through the rod 58 and the tubular member 30 for distribution by the cone 54 to the drill shoe I El.

. :After the drill been rotated in one direction and the-drillingoperation has been continued for a sufiicient time to bring the top of the US$535 near-to the cone '54, rotation of the drill in the drilling direction is stopped and rotation of the drill :rod 5% is reversed. Friction between the walls of the hole 63 and the barrel 4 holds the barrel stationary,while the reversal of rotation of the rod 58 is commenced with. This causes the member to be threaded down'the member 28 causing a corresponding downward movement in the puller 5 relative to thebar el and the wedge member i6. Continued rotation of the rod 56 in this fashion finally brings the dogs 52 into contact with the wedge ring it and forces them against the core 56. Sufiicient force is readily applied through the rod 58 to cause the wedge dogs 52 to grasp firmly the core 66. When this happens, rotation of the rod 58 is discontinued and sufficient hoisting pull is applied to the rod 58to break the core loose and then lift the device Z out of the hole along with the core 65.

As stated before, the description above and the drawing relate to a preferred type of apparatus which may be modified to some extent, while, at the same time, utilizing the basic new concepts of construction for drilling devices as provided by this invention. Thus, cone 54 can be omitted and various units, such as the wedge ring l6 and plate 2% can be formed as an integral part of their associated members ill and 22 respectively, if this is desirable from the aspect of construction. Whatever minor modifications of this type are made, the new devices of this invention eliminate the need for using separate core pullers in shot core drilling operations. As a result, it is possible to ,rnaterally increase the rate of drilling at a given location and also to eliminate the need for separate hoisting connections or the like, as is the case with separate core barrels and core pullers. 3y providing core drilling devices which can-bothdrill and lift a core through the use of a single drill rod, ifurther advances in the scope of usefulness of shot core drills can be realized.

The devices of this invention may be used for substantially all applications for which related units provided heretofore have been known to be useful, but these new units are distinguished'from the priorstructures in possessing additional-capabilities. For example, it is often found impossible to break th core off at the bottom, and this has created a serious problem in :the past. Now, however, the problem is generally overcome by the present apparatus since it is possible'ii the 'core can not be broken at the base, to retract the core puller, and raise the puller and drill up a short distance and again apply the puller to the core. In a majority of the cases, this operation, or a repetition thereof, permits the core to be broken at a point which allows sufficient core to be removed to continue the drilling, 9. g, at a bedding'plane. All this, of course, is accomplished without need to remove drill or puller from the hole or'similar troublesome operations. In addition, broken rock 'can be easily removed: eliminating another important trouble in this art.

We claim:

1. A shot core drilling device comprising-in combination a core barrel carrying a drill shoe at its lower end, a wedge ring on 'thetop of said shoe, a contractible, slotted, cylindrical core puller disposed coaxially within the 'core barrel having wedge dogs'on the lower end, a head plate fixed across the upper end of said barrel, an inside threaded tubular member fastened in the center of the head plate coaxially with the barrel an outside threaded tubular member threaded through said inside threaded member, a support member fixed to the top of the core puller and rotatably connected to said outside threaded member, a key plate fixed to said outside threaded member between said head plate and said support member and a key member fixed upon the bottom side of said head plate for operative en-. gagement with said key plate.

2. A drilling device as claimed in claim v1 wherein said support member comprises .a plate fixed across the top of said core puller.

3. A drilling device as claimed in claim 1 wherein said head plate is'composed'of twosections, the first section being a plate welded at its outside edge to the inside of the core barrel, said plate having a hole in the center thereof, the second part being a-plate of smaller diameter than said first plate fastened by holding means over said hole in said first plate.

4. A drilling device as claimed in claim 1 wherein a shot dispersing cone is carried within said core puller below said support member with the apex of the cone substantially at the center 3 of the opening in said inside threaded tubular member.

5. A shot core drilling device comprising in combination a core barrel, a slotted drill shoe fixed to the lower end of the core barrel, a grooved wedge ring fixed upon the top edge of said drill shoe tapering in from the shoe edge to the inside of the core barrel, a contractible slotted, cylindrical core puller disposed coaxially within the core barrel, wedge dogs on the lower end of the core puller, a plate fixed to the upper end of the core barrel forming a sludge chamber in the top thereof, a central hole in said plate, a second plate smaller in diameter than said first plate covering said hole bolted to said first plate, a central hole in said second plate, an inside threaded tabular member fixed to said second plate above said second plate hole coaxially to the core barrel, an outside threaded tubular member threaded through said inside threaded member, a, support plate fastened across the top 01 said core puller having a central hole therein to receive the lower end of said inside threaded tubular member, a key plate fixed upon the inside threaded member between said support plate and said barrel plate, a bearing between said key plate and saidvsupport plate, a hearing beneath said support plate, a not on the end of the inside threaded tubular member compressing said bearings against the sides of said support plate, and key members fixed to said second plate for operative engagement with corresponding key members carried by said key plate.

FRANK C. STURGES.

RUSSELL B. STROPE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 0 Number Name Date 2,214,238 Stovall Sept. 10, 1940 2,343,805 Sewell Mar. 7, 1944 

